* [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set()
@ 2016-01-30 11:54 Rafael J. Wysocki
2016-02-01 14:15 ` Andy Shevchenko
2016-02-03 9:58 ` Ulf Hansson
0 siblings, 2 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-01-30 11:54 UTC (permalink / raw)
To: Linux PM list
Cc: Linux Kernel Mailing List, Andy Shevchenko, Tomeu Vizoso,
Ulf Hansson, Kevin Hilman
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
to set the pm_domain pointer for devices with a driver bound.
However, that WARN_ON() triggers on attempts to clear the pointer
too and the test it uses is based on checking the device's
p->knode_driver pointer which still is set when the device bus
type's/driver's ->remove callback has been executed. This
leads to false-positive warnings when bus type code calls
dev_pm_domain_set() to clear the pm_domain pointer after
invoking the driver's ->remove() callback.
To avoid those false-positives, make dev_pm_domain_set() check
if the pointer passed to it is NULL and skip the warning in
that case.
Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/base/power/common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-pm/drivers/base/power/common.c
===================================================================
--- linux-pm.orig/drivers/base/power/common.c
+++ linux-pm/drivers/base/power/common.c
@@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de
if (dev->pm_domain == pd)
return;
- WARN(device_is_bound(dev),
+ WARN(pd && device_is_bound(dev),
"PM domains can only be changed for unbound devices\n");
dev->pm_domain = pd;
device_pm_check_callbacks(dev);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set()
2016-01-30 11:54 [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set() Rafael J. Wysocki
@ 2016-02-01 14:15 ` Andy Shevchenko
2016-02-03 9:58 ` Ulf Hansson
1 sibling, 0 replies; 5+ messages in thread
From: Andy Shevchenko @ 2016-02-01 14:15 UTC (permalink / raw)
To: Rafael J. Wysocki, Linux PM list
Cc: Linux Kernel Mailing List, Tomeu Vizoso, Ulf Hansson, Kevin Hilman
On Sat, 2016-01-30 at 12:54 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
> to set the pm_domain pointer for devices with a driver bound.
>
> However, that WARN_ON() triggers on attempts to clear the pointer
> too and the test it uses is based on checking the device's
> p->knode_driver pointer which still is set when the device bus
> type's/driver's ->remove callback has been executed. This
> leads to false-positive warnings when bus type code calls
> dev_pm_domain_set() to clear the pm_domain pointer after
> invoking the driver's ->remove() callback.
>
> To avoid those false-positives, make dev_pm_domain_set() check
> if the pointer passed to it is NULL and skip the warning in
> that case.
Tested on Intel Braswell where modprobe -r sdhci-acpi caused a warning
before this patch.
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
> Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/base/power/common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-pm/drivers/base/power/common.c
> ===================================================================
> --- linux-pm.orig/drivers/base/power/common.c
> +++ linux-pm/drivers/base/power/common.c
> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de
> if (dev->pm_domain == pd)
> return;
>
> - WARN(device_is_bound(dev),
> + WARN(pd && device_is_bound(dev),
> "PM domains can only be changed for unbound
> devices\n");
> dev->pm_domain = pd;
> device_pm_check_callbacks(dev);
>
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set()
2016-01-30 11:54 [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set() Rafael J. Wysocki
2016-02-01 14:15 ` Andy Shevchenko
@ 2016-02-03 9:58 ` Ulf Hansson
2016-02-03 12:08 ` Rafael J. Wysocki
1 sibling, 1 reply; 5+ messages in thread
From: Ulf Hansson @ 2016-02-03 9:58 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Linux PM list, Linux Kernel Mailing List, Andy Shevchenko,
Tomeu Vizoso, Kevin Hilman
On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
> to set the pm_domain pointer for devices with a driver bound.
>
> However, that WARN_ON() triggers on attempts to clear the pointer
> too and the test it uses is based on checking the device's
> p->knode_driver pointer which still is set when the device bus
> type's/driver's ->remove callback has been executed. This
> leads to false-positive warnings when bus type code calls
> dev_pm_domain_set() to clear the pm_domain pointer after
> invoking the driver's ->remove() callback.
>
> To avoid those false-positives, make dev_pm_domain_set() check
> if the pointer passed to it is NULL and skip the warning in
> that case.
>
> Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/base/power/common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-pm/drivers/base/power/common.c
> ===================================================================
> --- linux-pm.orig/drivers/base/power/common.c
> +++ linux-pm/drivers/base/power/common.c
> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de
> if (dev->pm_domain == pd)
> return;
>
> - WARN(device_is_bound(dev),
> + WARN(pd && device_is_bound(dev),
> "PM domains can only be changed for unbound devices\n");
Perhaps this information then becomes a bit misleading, as it's okay
to clear the pointer, but not assign it to a valid PM domain.
> dev->pm_domain = pd;
> device_pm_check_callbacks(dev);
>
Otherwise, this looks good to me!
Kind regards
Uffe
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set()
2016-02-03 9:58 ` Ulf Hansson
@ 2016-02-03 12:08 ` Rafael J. Wysocki
2016-02-03 13:18 ` Ulf Hansson
0 siblings, 1 reply; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-02-03 12:08 UTC (permalink / raw)
To: Ulf Hansson
Cc: Rafael J. Wysocki, Linux PM list, Linux Kernel Mailing List,
Andy Shevchenko, Tomeu Vizoso, Kevin Hilman
On Wed, Feb 3, 2016 at 10:58 AM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
>> to set the pm_domain pointer for devices with a driver bound.
>>
>> However, that WARN_ON() triggers on attempts to clear the pointer
>> too and the test it uses is based on checking the device's
>> p->knode_driver pointer which still is set when the device bus
>> type's/driver's ->remove callback has been executed. This
>> leads to false-positive warnings when bus type code calls
>> dev_pm_domain_set() to clear the pm_domain pointer after
>> invoking the driver's ->remove() callback.
>>
>> To avoid those false-positives, make dev_pm_domain_set() check
>> if the pointer passed to it is NULL and skip the warning in
>> that case.
>>
>> Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> ---
>> drivers/base/power/common.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> Index: linux-pm/drivers/base/power/common.c
>> ===================================================================
>> --- linux-pm.orig/drivers/base/power/common.c
>> +++ linux-pm/drivers/base/power/common.c
>> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de
>> if (dev->pm_domain == pd)
>> return;
>>
>> - WARN(device_is_bound(dev),
>> + WARN(pd && device_is_bound(dev),
>> "PM domains can only be changed for unbound devices\n");
>
> Perhaps this information then becomes a bit misleading, as it's okay
> to clear the pointer, but not assign it to a valid PM domain.
Well, this is a "you're doing a wrong thing" warning and it does say
what the wrong thing is. Does it have to be more specific? I don't
think so.
Thanks,
Rafael
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set()
2016-02-03 12:08 ` Rafael J. Wysocki
@ 2016-02-03 13:18 ` Ulf Hansson
0 siblings, 0 replies; 5+ messages in thread
From: Ulf Hansson @ 2016-02-03 13:18 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Rafael J. Wysocki, Linux PM list, Linux Kernel Mailing List,
Andy Shevchenko, Tomeu Vizoso, Kevin Hilman
On 3 February 2016 at 13:08, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Wed, Feb 3, 2016 at 10:58 AM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>> On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
>>> to set the pm_domain pointer for devices with a driver bound.
>>>
>>> However, that WARN_ON() triggers on attempts to clear the pointer
>>> too and the test it uses is based on checking the device's
>>> p->knode_driver pointer which still is set when the device bus
>>> type's/driver's ->remove callback has been executed. This
>>> leads to false-positive warnings when bus type code calls
>>> dev_pm_domain_set() to clear the pm_domain pointer after
>>> invoking the driver's ->remove() callback.
>>>
>>> To avoid those false-positives, make dev_pm_domain_set() check
>>> if the pointer passed to it is NULL and skip the warning in
>>> that case.
>>>
>>> Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>> ---
>>> drivers/base/power/common.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> Index: linux-pm/drivers/base/power/common.c
>>> ===================================================================
>>> --- linux-pm.orig/drivers/base/power/common.c
>>> +++ linux-pm/drivers/base/power/common.c
>>> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de
>>> if (dev->pm_domain == pd)
>>> return;
>>>
>>> - WARN(device_is_bound(dev),
>>> + WARN(pd && device_is_bound(dev),
>>> "PM domains can only be changed for unbound devices\n");
>>
>> Perhaps this information then becomes a bit misleading, as it's okay
>> to clear the pointer, but not assign it to a valid PM domain.
>
> Well, this is a "you're doing a wrong thing" warning and it does say
> what the wrong thing is. Does it have to be more specific? I don't
> think so.
Okay! I don't have a strong opinion.
Feel free to add:
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Kind regards
Uffe
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-02-03 13:18 UTC | newest]
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2016-01-30 11:54 [PATCH] PM: Avoid false-positive warnings in dev_pm_domain_set() Rafael J. Wysocki
2016-02-01 14:15 ` Andy Shevchenko
2016-02-03 9:58 ` Ulf Hansson
2016-02-03 12:08 ` Rafael J. Wysocki
2016-02-03 13:18 ` Ulf Hansson
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